Hello!!
Anyone here who have experience with such a conversion?
What does it takes? I know companies who deal with conversions like this, but they charge more than my budget.
Do I need an adapterplate or is it a strait fit? I have actually heard both.

Thanks!

Probably because nobody has any experience in the matter.

There is/was a UK outfit selling a kit for this conversion (probably the same company the OP was referring to) but the cost is extremely high....about $5000  last time I checked (years ago).

Not that mine is the final word but I've not heard of any other company offering the kit nor heard of any DIYers striking out on their own.

Here is the 'States we have a company selling a kit to install a GM 4-speed automatic. It's a very popular swap and usually runs about $1800-$2500 all-in...mostly depending if you install a used transmission "as-is" or spend extra for a pre-emptive overhaul before installation.

Cheers
DD